It is well known how to prepare a dispersion containing a metal base that is normally insoluble in an oil of lubricating viscosity such as lithium hydroxide. The dispersion containing the metal base has a low solids content (i.e. the amount of metal base in the dispersion) typically up to about 10 wt %. A dispersion of this type with a solids content greater than about 10 wt % are unstable without the presence of a large amount of surfactant to stabilise the dispersion against the metal base dropping out and forming sediment. Also a low solids dispersion contains a large amount of a carrier medium (often an oil of lubricating viscosity) and this makes transportation, storage, and dispensing of said dispersion difficult due to the volume of the medium. Furthermore, this makes the dispersion less environmentally friendly and expensive.
International Publication WO 04/026996 discloses a fuel additive composition capable of reducing vanadate deposits. The composition contains a metal inorganic oxygen containing compound, a liquid soluble in oil and a dispersant including fatty acid or ester derivatives thereof.
U.S. Pat. No. 3,067,018 discloses a colloidal additive for a fuel comprising a magnesium hydroxide with a solids content of 35 weight percent or less of the colloidal additive.
International Publication WO 03/044138 discloses a composition containing an oil of lubricating viscosity, at least one emulsifier capable of forming a water-in-oil emulsion, a base and optionally an oil insoluble solvent. The base includes metal salt of a hydroxide, a carbonate, a bicarbonate or an amine salt of an organic acid. The composition does not disclose a dispersion with a high solids content. Furthermore the dispersion is suitable for marine lubricants.
U.S. Pat. No. 2,434,539 discloses that a strong metal hydroxide may be made more reactive to high molecular weight organic fatty acids by heating the metal hydroxide crystals in the presence of a liquid hydrocarbon to a temperature and for a sufficient time to drive off all water of crystalisation i.e. at a temperature above 107° C.
U.S. Pat. No. 2,394,907 discloses suspending an alkali or other saponification agent in a non-reactive liquid medium and mechanically comminuting the alkali in oil until a predominant portion of the particles of alkali is as low as 5 micrometers in size. The resultant alkali is then used to make grease.
U.S. Pat. No. 4,075,234 relates to grease manufacture using a concentrated aqueous solution of lithium hydroxide in a liquid reaction mixture comprising an alkyl nitrile.
U.S. Pat. No. 4,337,209 relates to a method of preparing soap and greases by reacting an organic carboxylic acid, its esters and mixtures thereof with a concentrated aqueous solution of alkali metal hydroxide in the presence of an inorganic salt, in a liquid reaction medium comprising acetone. The presence of the inorganic salt increases the yield of the soap or grease.
U.S. Pat. No. 5,236,607 relates to a process for preparing a lithium soap thickened grease which consists of heating a mixture of oil and a lithium base to at least 100° C., then heating the resulting mixture at a temperature in the range of 110° C. to 200° C. until a thickened grease is obtained. After the grease is formed it is subjected to a homogenization/milling process resulting in a smooth grease.
It would be desirable to have a dispersion composition with a high solids content. The present invention provides a dispersion composition capable of providing a composition with a high solids content.
It would be desirable to have a dispersion composition with a high solids content capable of being used as a thickener for grease manufacture. The present invention provides a dispersion composition capable of being used as a thickener for grease manufacture.
It would be desirable to have a dispersion composition with a small particle size with a high solids content and with a low viscosity. The present invention provides a dispersion composition with a small particle size with a high solids content and with a low viscosity.